Homework Help:
Fluids - I wish the answer would flow to me

I have two problems to do and I seem to suck at fluids...:tongue:
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The drawing shows a hydraulic system used with disc brakes. The force F is applied perpendicularly to the brake pedal. The brake pedal rotates about the axis shown in the drawing and causes a force to be applied perpendicularly to the input piston (radius = 9.53 10^-3m) in the master cylinder. The resulting pressure is transmitted by the brake fluid to the output plungers (radii = 2.14 10^-2m), which are covered with the brake linings. The linings are pressed against both sides of a disc attached to the rotating wheel. Suppose that the magnitude of F is 9.18 N. Assume that the input piston and the output plungers are at the same vertical level and find the force applied to each side of the revolving disc.
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A solid cylinder (radius = 0.150 m, height = 0.120 m) has a mass of 6.60 kg. This cylinder is floating in water. Then oil ( = 725 kg/m3) is poured on top of the water until the situation shown in the drawing results. How much of the height of the cylinder is in the oil?

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I tried everything I could think of but just don't get it, could I have some clues? Thanks.